Detection of Siglec‑1/CD169 in Human PBMCs by Flow Cytometry. Human peripheral blood mononuclear cells (PBMCs) either (A) untreated or (B) treated with 20 ng/mL Recombinant Human IFN‑ gamma (Catalog # 285-IF) for 24 hours were stained with Mouse Anti-Human Siglec‑1/CD169 Monoclonal Antibody (Catalog # MAB5197) followed by Allophycocyanin-conjugated Anti-Mouse IgG Secondary Antibody (Catalog # F0101B) and Mouse Anti-Human CD14 PE‑conjugated Monoclonal Antibody (Catalog # FAB3832P). Quadrant markers were set based on control antibody staining (Catalog # MAB002).
Preparation and Storage
Reconstitute at 0.5 mg/mL in sterile PBS.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. *Small pack size (SP) is shipped with polar packs. Upon receipt, store it immediately at -20 to -70 °C
Stability & Storage
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
6 months, -20 to -70 °C under sterile conditions after reconstitution.
Siglecs are sialic acid specific I-type lectins that belong to the immunoglobulin superfamily. Structurally, they are transmembrane proteins with an N-terminal Ig-like V‑set domain followed by varying numbers of Ig-like C2-set domains (1, 2). Human Siglec-1, also known as sialoadhesin and CD169, is a 175-185 kDa glycoprotein. It contains a 1622 amino acid (aa) extracellular domain (ECD) with one Ig-like V‑set domain and 16 Ig-like C2-set domains, a 21 aa transmembrane segment, and a 44 aa cytoplasmic domain (3). Within the ECD, human Siglec-1 shares approximately 70% aa sequence identity with mouse and rat Siglec-1. Alternate splicing generates a potentially soluble form of the ECD, and a second isoform with a substituted cytoplasmic domain. Siglec-1 expression is restricted to lymph node and splenic macrophages, plus some tissue macrophages (3). The adhesive function of Siglec-1 is supported by the N-terminal Ig-like domain which shows a selectivity for alpha 2,3‑linked sialic acid residues (3‑5). Siglec-1 binds a number of sialylated molecules including the mannose receptor, MGL1, MUC1, PSGL-1, and different glycoforms of CD43 (6‑9). Its binding capacity can be masked by endogenous sialylated molecules (10, 11). The sialylated and sulfated N-linked carbohydrates that modify Siglec-1 itself are required for ligand binding (6, 7). Siglec-1 is expressed on dendritic cells following rhinovirus exposure, and these DC promote T cell anergy (12). It is also induced on circulating monocytes during systemic sclerosis and HIV-1 infection (13‑15). Siglec-1 can trap HIV-1 particles for trans infection of permissive cells (14).
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Sialic Acid Binding Ig-like Lectin 1
Entrez Gene IDs:
6614 (Human); 20612 (Mouse); 311426 (Rat)
C19orf75; CD169; Siglec1; SIGLECL1 SIGLEC family like 1
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